i feel like the author most likely read 'i am a hero' because of this similarity: time shenanigans where the 'hybrid zombie' character (kou in this manga and hiromi in 'i am a hero') inhabits notable zombies at various points in time. i am 90% sure that the author intended to tell their take on an 'i am a hero'-like story, but the manga probably just ended up being shorter than they wanted.
i think there was a lot of potential in this manga, such a shame it went to waste.